Rock drill



.July 5, 1932. K. M. PERRY ROCK DRILL Filed March 1929 INVENTOR I BY wyfin/m fm ATTORNEYS KENNETHJ'LPERRY Patented July 5, 1932 UNITED STATESPATENT OFFICE.

KENNETH M. PERRY, OF MONTREAL, QUEBEC, CANADA, ASSIGNOR TO GEORGE C.RILEY,

' OF MONTREAL, CANADA 7 ROCK DRILL Application filed March 8,

This invention relates to new and useful improvements in rock drills andparticularly to drills percussively driven and rotated and adapted formine, quarry and other similar drilling operations.

The object of the invention is to provide a rock drill having aseparable cutter head or bit so attached to the drill rod that theimpact from the rock drilling machine is transmitted through the drillrod to the bit over a maximum area and on a plane at right angles to thedirection of the blow.

A further object is to provide a rock drill with a. removable bitattached to the drill rod by a member which will be accessible so thatthe bit maybe quickly detached for repairs,

inspection or other purposes.

A still further object is to provide a removable cutter head or hit soattached to the rod 29 that the maximum diameter of the rod is less thanthe maximum diameter of the bit, such differences in diameter beingsuflicient to allow for clearance of the cuttings. A still furtherobject is to provide a bit of small dimensions and weight so that it can1 be economically manufactured. easily transported or carried to thedrilling face and quickly and conveniently attached to the drill rod.

According to my invention, I provide a rock drill and a cutter head orhit held together by a connecting member, the head of which fits into arecess formed in the cutting face of the bit. The threaded shank of theconnecting member passes through a hole'in the cutter and engages with athreaded socket formed in the end of the drill rod. The length of thethreaded socket is such that the endof the connecting member cannotcontact with the bottom of the socket to transmit the percussive blowsfrom the rock drill through the rod and bolt to the surface beingdrilled. The bolt or connecting member is adapted to draw the abuttingsurfaces of the drill rod and the bit together so that the percussiveblows from the drillingmach'ine are trans mitted directly by the drillrod to the bit through their contacting faces which are at 5 rightangles to the direction of the saidblows.

'for the passage therethrough 1929. Serial No. 345,535.

f In the drawing which illustrates my inven Figure 1 is a perspectiveview showing a bit and a drill rod in assembled relation and madeaccording to my invention.

Figure 2 is a part sectional elevation of the drill rod, bit andconnecting member in assembled relation.

Figure 3 is a part sectional elevation showing the parts of the drillbefore assembly.

F igue4 is an end View of the connecting member.

Referring more particularly to the drawing, 11 designates a drill rodwhich for illustrative purposes is shown hexagonal in as cross sectionfor substantially its full length merging into a rounded section towardsthe end 12. This dl'lll rod has a central hole 13 extending through thefull length of the rod of a cooling and lubricating agent. The face 14of the rod is at right angles to the aXis 15-15. Extending into the rodat the end 12 and from the face 14 is the threaded socket 16 adapted toengage with the threaded shank 17 of the connecting member 18. Thismember is pro-- vided with a central hole adapted to coincide with thehole in the drill rod. A bit 19 having a cutting surface 20 is providedwith a recess 21 adapted to receive the head 22 of the connectingmember. The head contacts with a shoulder 23 formed between the hole 24and the recess 21. The shank of the connecting memberf passes throughthe hole 21 and engages with the threaded socket in the drill rod. Thedepth of the head is preferably made smaller than the depth of therecess so that the head lies below the cutting face of the bit. The face25 of the bit remote from the cutting face is drawn against the adjacent face of the rod by the connecting member and the length of saidmember is such that at no time during the operation of the drill can theend of the connecting member contact with the bottom of the socket.

The end of the bit abutting the drill rod is preferably of the samediameter as the rounded portion of the rod so that when the abuttingfaces are drawn together, they will present the maximum surface fortransmit- 1 machine through the recess in the cutting blows from thedrilling drill rod directly to the bit. The maximum diameter of thecutting face of the bit is larger than the diameter of the drill rod,and the difference in diameter is such that cutting clearance isallowed.

This means that the wings of the bit have a'gradual slope merging intothe outer diameter of the drill rod so thatan unimpeded passage ispresented for the egress of the cuttings made by the bit and there areno protrusions or shoulders which would interfere with the free workingof the drill. The connecting member or bolt may be made comparativelysmall in diameter as its duty is only to hold the adjacent faces of thebit and rod together. The head of the con necti'ng member may beprovided with diametrically opposite flattened portions to facilitatethe assembly or dismantling of the drill. The connecting member may bemade of metal, the main feature. of which is its tensile strength.'Thelrod may be made of ting the percussive a metal suitable forwithstanding the shock and fatigue due to the percussive and rotatingaction of the drilling machine (notshown). The bit may be made from ametal different from the rod as the main qualities of the bit is theretention of a cutting edge. The bit is made small and light and iseasily carried to the working face.

In operation, it will be geen that no threaded portions are expose whichmay become damaged through contact with the rock or the like. The rod isinternally threaded so that the thread is protected from damage. Theconnecting members are light and inexpensive and very easily replaced.When the rod and connecting member are provided with central holes,lubricating and cooling fluid may be fed to the drilling face.

In the drawing, a rock:drill is shown but it will be evident that theconnection may be used with substantially the same beneficial results onother types of drills.

\Vhat I claim is:

1. A rock drill comprising a drill rod, provided with a longitudinallyextending bore,

the'end of thebore adjacent to the bit engaging end of the rod beingenlarged and internally threaded, a to engage the said end of the drillrod, said bit being provided with a central bore aligned with the socketin the drill rod, the outer end of the bore being enlarged to form acentral face of the bit, and a bolt having a longitudinally extendinggroove passing" through the bore of the bit with the head of the boltcountersunk in said recess and the shank of the bolt threaded into thesocket formed in the drill rod, but termiand terminating at ing facecontained in a plane perpendicular to said bore, the end of the boreadjacent to saidv bit engaging internally threaded, abit havinga base Inwitness whereof, I have hereunto set my hand.

KENNETH M. PERRY.

one end in a flat bit engag- I face being enlarged. and. a

bit having a base adapted nating in spaced relation to the bottom wallof the socket.

2. A rock drill comprising a drill rod rovided with a longitudinallyextending bore

